1. Field of the Invention
The invention relates to a heating valve where a stem passes through a packing nut, a tubular section and a bonnet for forming a seal.
2. Brief Description of the Background of the Invention Including Prior Art
Heating valves have been taught in German Patent DE-PS No. 2,042,244, where the tube is produced by hollowing out by turning of a massive rod section. Such a method of production is expensive with respect to material and labor and is therefor high-cost. In addition, the tube produced by turning out of a massive rod section is provided with only an annular bottom face, while an annular top face is formed by a pressed in stop ring. In order to avoid that the pressed in annular stop ring is pushed out again by the force of the spring, the edge of the tube toward the top is slightly inclined toward the inside. Upon screwing in of the packing nut into the bonnet the stop ring seated in a pressure fitting in the tube is pressed down further in the tube. Such a construction of the upper part of a valve has proven to be functional, however for the closing of the upper end of the tube an additional part is required in form of the stop ring.